1. Field of the Invention
The present invention relates to a metallic Mg electrolyzing device for forming metallic Mg by electrolysis of molten salts containing chloride of Mg, in particular, to a metallic Mg electrolyzing device provided with a plurality of electrolytic cells, Cl.sub.2 gas produced as a byproduct therein being collectively sucked.
2. Discussion of the Background
A metallic Mg electrolyzing device industrially used for forming metallic Mg by electrolysis of molten salts containing chloride of Mg uses a plurality of electrolytic cells, in each of which formation of metallic Mg is carried out simultaneously. And with the formation of metallic Mg, Cl.sub.2 gas is produced as a byproduct in each electrolytic cell. The Cl.sub.2 gas produced as a byproduct in each electrolytic cell is collectively sucked by use of an aspirator installed in the main pipe through branch pipes and transported to a Cl.sub.2 gas refining equipment.
In such a metallic Mg electrolyzing device provided with a plurality of electrolytic cells, in order to improve current efficiency and decrease electric power consumption rate, it is important to control the suction pressure for sucking Cl.sub.2 gas in each electrolytic cell to a slight negative pressure of -10 to 0 mmH.sub.2 O (-0.1 to 0 kPa). The reason is that, if the suction pressure becomes higher, the ratio of the atmospheric air mixed into electrolytic cell is increased, which leads to reducing current efficiency.
In the prior art, however, since negative pressure was not controlled individually in each electrolytic cell, the suction pressure for sucking Cl.sub.2 gas in each electrolytic cell was not controlled to -10 to 0 mmH.sub.2 O, which caused reduction in current efficiency.